A novel concept for evaluation of pulmonary function utilizing PaO2/FiO2 difference at the distinctive FiO2 in cellular ex vivo lung perfusion-an experimental study.

For more accurate lung evaluation in ex vivo lung perfusion (EVLP), we have devised a new parameter, PaO /FiO ratio difference (PFD); PFD  = P/F ratio at FiO 1.0 - P/F ratio at FiO 0.4. The aim of this study is to compare PFD and transplant suitability, and physiological parameters utilized in cellular EVLP. Thirty-nine human donor lungs were perfused. At 2 h of EVLP, PFD was compared with transplant suitability and physiological parameters. In a second study, 10 pig lungs were perfused in same fashion. PFD was calculated by blood from upper and lower lobe pulmonary veins and compared with lobe wet/dry ratio and pathological findings. In human model, receiver operating characteristic curve analysis showed PFD had the highest area under curve, 0.90, sensitivity, 0.96, to detect nonsuitable lungs, and significant negative correlation with lung weight ratio (R  = 0.26, P < 0.001). In pig model, PFD on lower and upper lobe pulmonary veins were significantly associated with corresponding lobe wet/dry ratios (R  = 0.51, P = 0.019; R  = 0.37, P = 0.060), respectively. PFD in EVLP demonstrated a significant correlation with lung weight ratio and allowed more precise assessment of individual lobes in detecting lung edema. Moreover, it might support decision-making in evaluation with current EVLP criteria.